Acid soils

Surface and subsoil acidity occurs extensively across SA’s cropping and grazing lands. It’s estimated that more than two million hectares of agriculture is susceptible to soil acidification.

Over the next 10 to 50 years this area prone to acidification is likely to double, under current farming systems.

Soil acidification is a natural process, but the rate of acidification is increasing due to:

higher rates of nitrogen (N) fertiliser application

increase in cropping/hay intensity and yields

nitrate leaching under crops and pastures.

Soil acidity issues have historically occurred in the higher rainfall areas including the South East, Adelaide Hills, Kangaroo Island, but are becoming more widespread in the medium and high rainfall cropping areas such as the Mid North and on the Eyre Peninsula.

Soil acidity is increasing in its extent and severity under high-yielding, continuously cropped farming systems in southern Australia.

Projects

PIRSA is working and collaborating on a number of projects including trials aimed at:

comparing new lime sources

comparing approaches to treating subsurface acidity

raising awareness with agribusiness and landholders

determining rates of acidification

the development of tools to help grain growers manage soil acidity by being able to compare the economics of liming products, audit acidity on farm and determine the cost of acidity.

The projects involve input and investment from the Grains Research and Development Corporation (GRDC), farming systems groups, the Agricultural Bureau of South Australia, Landcare groups, various regional Natural Resource Management Boards, the Department of Environment and Water (DEW), and the Australian Government.